75T/H Lignite Fired CFB Boiler Superheater And Reheater CE Standard

ASME or CE Standard Seamless Carbon Steel Superheater for 75 T/H Lignite Fired CFB Boiler

Arrnagement and specification:
The boiler has high and low superheaters, the HS is arranged in the flue gas duct after cyclone separators, and the LS is arranged in back-end vertical shaft. The saturated steam is introduced into the ceiling enclosure headers by eight φ108×5 saturated steam connecting tubes on the drum, and then into the lower temperature superheater through φ 42×4.0 tubes, after being heated by LS, goes into desuperheater for adjusting temperature, and then goes into HS through eight tubes of φ108×5, and sent to steam turbine through main steam valve after going into SH outlet header.
The LT superheater adopts contranatant arrangement and the HT superheater is downstream arrangement. The collection and distribution of steam adopts the way of width direction to improve non-uniformity of steam flowing and prevent local coils superheated due to steam deflection.

Material:
To ensure safety operation, the LT superheater uses SA210 Gr.A1 seamless steel tubes, and the HT superheater uses low-alloyed SA213 T22 seamless steel tubes.

Working Principle

Superheater is the part that heats the steam from the saturation temperature to the superheater by the boiler. It is also called the superheater.
Superheater can be divided into convection type, radiant type and semi-radiant type according to heat transfer mode;
According to the characteristics of the structure, it can be divided into serpentine tube type, screen type, wall type and wall type.

They all consist of a number of parallel pipes and inlet and outlet manifold.
Most industrial boilers do not have superheaters because many industrial processes and utilities require only saturated steam.
Superheaters are generally installed in power stations, locomotives and Marine boilers to improve the thermal efficiency of the entire steam power plant.

Super heater types:
1. Radiant super heater: it is the earliest type of super heater and it is located above or behind banks of water tubes to protection them from direct flam or fire.
Parameters that increases the convection

a. Increasing the fuel-and air flow (combustion gas flow)
b. Increasing the mass flow rate of the steam

Radiation is mainly dependent on the flam temperature. as the steam flow rate increases the exit temperature become lower.
Radiant super heater
They are placed exposed to the heat source whcih requires the improvement of metal temperatures.

Radiant and convetive super heaters and reheaters are used for high temperature steam.
The accessory of high temperature radiant steam super heater in boiler

It is made up of snake-like tubes (carbon steel, alloy steel or heat-resistant steel, etc.) and collection boxes and other supporting material. Tubes generally have φ32, φ38, φ42 or other types of specifications, according to user's needs separately.

Reheaters
They are the sane as the super heaters but as their exit temperature is a little bit less than super heaters and their pressure is 20% -25% less than the super heater, they can stand less quality material alloys.

Application:
Steam super heater is consisted of dense tube coils and is placed in the flue under the tempearture 450ºC-1000ºC.
For power plant boiler capacity over 10Mpa, platen and coiled superheater are usually adopted.

What are the differences of Superheater And Reheater?